Reputation: 557

Passing data from view to view?

I am making an application solely for the purpose of learning more objective c. This application basically takes a user to a modal view and then gives the user options (uibuttons) to click. When a user taps a button, the modal view is dismissed and I would like to take the data taken from that button (whether it's the title of the button, tag, etc, whichever is easiest to use) and store it as a variable in my main view. I have tried using an extern NSString defined in a seperate .h file, but no luck. What am I missing?

Upvotes: 0

Answers (5)

Hemang

Reputation: 27050

suppose you've two viewcontrollers say A & B

Your A.h

{
  NSString *strData;
  int cId;
}

@property (nonatomic, retain) NSString *strData;
@property (readwrite) int cId;

Now In your A.m

@synthesize strData,cId;

Your B.h

@class A

{
   A *aObj;
}

Now In your B.m

#import "A.h"

- (void) viewDidLoad
{
  aObj=[A alloc] init]; //alloc object of A
  [aObj setCId:10]; //set value for cId
  [aObj setStrData:@"Hello from B"]; //set value for strData
  //do what ever
  [aObj release]; //don't forget
}

Upvotes: 0

Kanan Vora

Reputation: 2122

You can store the data in an object in the appDelegate which is the Delegate file for the applications,

You can declare an object in appDelegate:

NSString *buttonName;

Then propertise and synthesise that object.

After doing this, put a code in the View Controller which you are opening as a Modal VIew:

appDelegate.buttonName = yourbutton.titleLabel.text;

Now even after dismissing the modal view, you'll be having the button's title stored in the appldelegate's object, and you can access it from any where in your application.

Upvotes: 0

Adil Soomro

Reputation: 37729

use delegations. make a protocol.

@protocol SelectValueDelegate <NSObject>
@optional
- (void) selectedValue:(NSString * )values selectionViewController:(UIViewController *)controller;
- (void)selectionCanceled:(UIViewController *)controller;
@end

implement it inside your MainViewController.h

@interface MainViewController : UIViewController<SelectValueDelegate> {
    //.... 
}

and .m file looks like this:

- (void) selectedValue:(NSString * )values selectionViewController:(UIViewController *)controller
{
    //here you have value.
    [controller dissmissModalViewControllerAnimated:YES];
}
- (void)selectionCanceled:(UIViewController *)controller
{
        [controller dissmissModalViewControllerAnimated:YES];
}

and in you ModalViewController make a property of delegate like this:

@interface ModalViewController : UIViewController
        id<SelectValueDelegate> delegate;
}
@property(assign)id delegate; // synthesize it also

now on click of button do something like this:

-(IBAction)buttonClicked:(id)sender
{
       [delegate selectedValue:@"Value" selectionViewController:self];
}

and when presenting it modally inside MainViewController, do something like this:

ModalViewController *screen = [[ModalViewController alloc] initWithBlahblah];
screen.delegate = self;
[self.navigationController presentModalViewControllerAnimated:YES];

Upvotes: 1